Einfluß von Bodenbearbeitung, Kulturart und Zwischenfruchtanbau auf den Bodenabtrag und den Oberflachenwasserabfluß

The effects of different soil tillage systems, crop rotations and short time cover crops on soil losses and runoff
Soil and water losses were carried out from 1979 to 1986 on a pseudogley-parabrownearth of the farm Ihinger Hof throughout the growth period of green maize and sugar-beet, both planted by plough and rotary hoe. From 1983 to 1986 the effect of short time soil cover crops (October—Dezember) were also studied.
The soil losses under rotary hoe were significantly lower in comparison to plough, but the differences in runoff between the tillage treatments were not significant. Under sugar-beet the erosion caused by rainfall was less than under maize. From the short time soil cover crops, the legume mixtures were found to have the best influence on soil and water conservation, and on the maize growth as well. There was no relationship between runoff or rainfall amount and soil losses. The soil losses correlated strongly to EI₃₀-indices, and this means that the USLE equation of W ischmeier and S mith (1965) can be applied in our experimental Farm in Ihinger Hof.     

Untersuchungen zum Einfluß von Standort, Saatstärke, N-Düngung, Sorte und Erntezeitpunkt auf den Ertrag und die Inhaltsstoffe von Zuckerhirse

Investigations into the effect of location, planting density, N-fertilization, variety and harvest date on yield and contents of sweet sorghum
Looking for high yielding plant species as renewable resources, sweet sorghum ( Sorghum bicolor [L.] Moench) seems to be an interesting crop.
In field trials at three locations in the south-west of Germany in 1983 and 1984 should be investigated the effect of N-fertilization, planting density, variety and harvest date on yield, different morphological characteristics and contents of sweet sorghum.
The results indicate that yields of 15-20 t DM/ha are only feasible when the given temperature sum is higher than 2000 °C (> 5°C). The maximum yield of 22.7 t DM/ha resp. 6.5 t/ha "Free Fermentable Sugar" (FFZ) was realized when a sufficient water supply and N-fertilization had been guaranteed.
The different possibilities of utilization of sweet sorghum e.g. as sugar crop, agricultural raw material for combustion or as forage crop urge the plant breeder to intensify the breeding efforts adapting this crop at the climatic conditions of Germany.     

Erhaltung der Ertragsfähigkeit des Bodens auf lange Sicht unter dem Einfluß von Fruchtfolgegestaltung, Düngung und Herbizideinsatz

Impact of crop rotation, fertilizer treatments, and herbicidal applications on the long term maintenance of soil fertility
VI. Examination of progressive differences regarding chemical and physical factors of the yield potential of a soil conducted over the period 1973 through to 1983
In order to investigate the influence of different crop management practices such as crop rotation, fertilizer treatments, and herbicide applications on the yield potential of a soil, the Crop Science Department of the Swiss Federal Institute of Technology (ETH Zürich) conducted a long term field experiment commencing 1973. The experimental location was at the Swiss Federal Research Station for Farm Management and Agricultural Engineering at Tänikon/TG (northeastern Switzerland).
Over ten years of research it was found that chemical and physical soil properties had, in general, been only marginally affected by the different experimental treatments. However, consistent studies have shown that certain trends regarding specific factors of greater importance have emerged, which were not observed during the first five year period. Should they persist, the yield potential of the soil could be substantially affected in the long run.
Soil reaction, organic carbon content, cation exchange capacity, and aggregate stability have proven to be relatively stable values. Changes of greater significance were evidenced regarding the character of the air-water regime, a factor of particular importance for this site. Obviously, crop rotation had a marked impact on soil compaction. Therefore under local research conditions, the yield potential of the soil will, in the short term, be most likely endangered by structural soil changes.     

Erhaltung der Ertragsfähigkeit des Bodens auf lange Sicht unter dem Einfluß von Fruchtfolgegestaltung, Düngung und Herbizideinsatz

Impact of crop rotation, fertilizer treatments and herbicidal applications on the long term maintenance of soil fertility
V. Comparative studies regarding chemical and physical factors of the yield potential of a soil over a ten year experimental period
In order to examine the influence of different crop management practices such as crop rotation, fertilizer treatments and herbicide applications on the yield potential of a soil, the Crop Science Department of the Swiss Federal Institute of Technology (ETH Zurich) conducted a long term field experiment commencing 1973. The experimental location was at the Swiss Federal Research Station for Farm Management and Agricultural Engeneering at Tanikon/TG (northeastern Switzerland).
After the ten year period, chemical and physical soil properties were not found to be substantially affected by the various experimental treatments. Organic carbon and total nitrogen were more influenced by fertilizer treatments than by crop rotation and herbicide applications. Both cation exchange capacity and pH proved to be fairly stable values.
Aggregate stability and organic matter exhibited similar profiles, although soil bulk density was affected by crop rotation. The volume of large and medium sized pores was similarly affected in that the corn-dominated crop rotation resulted in a quantifiable impact upon soil compaction.
Depending upon weed control efficiency, the grain yields of the winter wheat test crop clearly exhibited the effects of crop rotation whereas the lowest yields resulted from the corn-dominated crop rotation.     

Einfluß verschiedener organischer Düngemittel auf die Effizienz von Azospirillum lipoferum

Effect of several organic manures on the efficiency of Azospirillum lipoferum
Under greenhouse conditions, it was examined how grass mulch, farmyard manure and compost influence the efficiency of Azospirillum lipoferum with Sorghum bicolor. The organic manures were added at 5 concentrations: 0, 50, 100, 200 and 300 dt/ha.
With the exception of the highest amount the grass mulch always induced a good effect of Azospirillum on plant yield and nutrient uptake. The application of farmyard manure or compost did not improve the growth of the inoculated plants. With farmyard manure the inoculation even lowered shoot dry weights. But in both treatments the inoculated plants showed considerably increased N and P contents. In addition to the N₂ fixation the inoculation with Azospirillum lipoferum apparently can increase the capacity of the sorghum plant roots to absorb P. Primarily, the organic manures create better growing conditions for the bacteria and simultaneously serve as P sources.     

Zum Einfluß von Saatzeiten, Saatstärken und Sorten auf agronomische Merkmale von Winterweizen in einem System mit geringer Betriebsmittelzufuhr von außen

The influence of sowing date, seed rate, and variety on agricultural characteristics of winter wheat in a low external input system
Growth conditions of winter wheat in agricultural low external input systems, e.g. ecological agriculture, are very different compared to conventional agriculture (mineral nutrition, impact of diseases, competition of weeds). In 1986, 1987, and 1988 the influence of sowing date and seed rate on crop development and grain production was studied with two varieties of winter wheat in field experiments in Northern Hessia.
Drilling after the first decade of October decreases grain yield of both varieties significantly. The decrease was due to poor emergence, low plant densities, and low grain weights. Tillering could not compensate low plant densities, presumably because of low mineralization of nutrients in cold soils during respective growth stages.
Variation of seed rate (350, 500, and 650 viable seeds/m²) had little influence on grain yield. Low plant densities and low numbers of ears per nr after sowing in the end of October could not be improved satisfactorily by increased seed rates.
The ability of varieties of winter wheat to compensate unfavourable growth conditions due to "late" sowing varies considerably. Cultivars which are able to develop a high plant density seem to be more suitable for delayed sowing dates, as compared to varieties which own a high grain weight.
Further investigations concerning wheat production are needed to optimize agricultural low external input systems. Especially sandy soils with quick response to increased ambient temperature, and sites with favourable growth conditions in late autumn and early spring should be considered.     

Einfluß des Standortes, der N-Düngung, der Sorte und des Erntezeitpunktes auf den Ertrag an fermentierbaren Zuckern bei Topinamburkraut und -knollen

Effect of location, N-fertilization, variety and harvest date on the yield of fermentable sugars of Jerusalem artichoke tops and tubers
In the past, the production of fermentable sugar with Jerusalem artichoke ( Helianthus tuberosus L.) resulted nearly exclusively from tubers.
It should be investigated to what extent the tops can be used beside tubers as a source of fermentable sugars, connected with studies about diverse components of yield and morphological characteristics.
In field trials at three locations in the south-west of Germany in 1983 and 1984 yields of "Total Fermentable Sugars" (TFZ) with Jerusalem artichoke tops up to 6.7 t/ha were achieved according to variety, N-fertilization and harvest date. While harvesting Jerusalem artichoke tubers yields of TFZ up to 8.3 t/ha had been feasible.
The presented correlations between components of yield and morphological plant characteristics refer to interesting mechanisms of reaction and dependence on the formation of yield with this crop. The high yield level of Jerusalem artichoke and its adaptability to different locations also present this crop as an interesting renewable biomass crop for the south-west of Germany.     

Ertragsbildung von getreidereichen Fruchtfolgen und Getreide-monokulturen in einem extensiven und intensiven Anbausystem

Yield formation in cereal-rich crop rotations and monocultures in an extensive and intensive crop-management system
In a long duration trial, conducted from 1979/80 to 1992 at TU-Munich's research station in Roggenstein, the performance of monocultures of winter wheat, winter barley and winter rye, as well as numerous cereal-crop rotations were compared in an extensive and intensive crop-management system. The results obtained can be summarized as follows.
Over the course of 13 years, the influence of the immediately preceding crop on the yield of the main crops was of much greater significance than the rotation as a whole. With winter wheat, no yield differences could be observed between monoculture and cereal crop rotation (if the rotation did not include oats). Oats, rape, field bean, pea, potato and maize as preceding crops, however, in crop management systems, led to, on average, an increase in yield of 13 dt/ha from the following wheat. Winter barley yields were not significantly different in monoculture, cereal crop rotations and crop rotations containing 66% cereals. Furthermore, winter rye yields were the same in monocultures and cereal crop rotations. With all cereals, intensification of fertilizing and chemical plant protection led to a considerable increase in yield, but did not diminish the effects of the preceding crop. Hence, even with the use of modern agronomical techniques it is impossible to compensate for yield losses due to crop rotation.     

Zum Einfluß von Untersaaten zur Begrünung von Ackerbrachen auf die Vegetationsentwicklung und die Nitratdynamik

The influence of undersown green manure crops for fallows – set-aside land – in view of vegetation-development and the dynamic of nitrate
In view of the establishment of rotational fallows - set-aside land - as well as the bridging of the vegetation-free winter period the suitability of different undersown grasses and legumes m winter cereals was investigated in field trials. Festuca rubra developed well in winter barley and winter wheat. The success of the cultivation of Lolium perenne, Trifolium pratense and Trifolium repens in winter cereals is uncertain because of the risk of light and water deficiences. Dactylis glomerata caused an negative influence on the yield of the cover crop. During the fallow period only low levels of nitrate could be found in the soil. Under fallow tilled repeatedly complete fallow- a nitrate accumulation could be observed during the fallow period. After ploughing up the fallow vegetation, nitrate concentrations - depth 0–150 cm – increased to 60 kg NO₃-N · ha^-1 after the natural fallow without seeding, between 60 and 130 kg NO₃-N · ha^-1 after Trifolium and between 160 and 210 kg NO₃-N · ha^-1 after complete fallow. Lowest nitrate levels were observed from the grass-sites. Undersown Festuca rubra seems to be the best choice in order to compete with weeds, to form a dense sod and to prevent nitrate leaching. In general a seed rate of 8 kg · ha^-1 can be recommended.     

Einfluß eines variierten N-Angebots auf α-Amylase-Aktivität, primäre Dormanz und Auswuchsresistenz von Weichweizen (Triticum aestivum L.), Roggen (Secale cereale L.) und Triticale (X Triticosecale Wittmack)

Influence of Varying N-Fertilization Rates on α-Amylase Activity, Primary Dormancy and Resistance to Pre-Harvest Sprouting in Wheat ( Triticum aestivum L.), Rye ( Secale cereale L.) and Triticale (X Triticosecale Wittmack)
Pre-harvest sprouting, induced by unfavourable ecological conditions, can affect the grain growers success considerably. Positive correlations are reported between resistance to pre-harvest sprouting and primary dormancy. Genotypes with a short dormancy period have a high pre-harvest sprouting risk. In the case of a premature germination of caryopses in the head of grain a hydrolysis of intact starch granules caused by the endoenzyme α-amylase takes place in the endosperm.
Negative correlations between falling number and protein content are reported, however, it is unknown, if a varying N-application influences pre-harvest sprouting rates, dormancy periods and amylase activity. For this reason, both greenhouse and field trials were conducted with different N-fertilization rates and (additional in the greenhouse) a rain simulation treatment.
High amounts of α-amylase a few days post anthesis are opposed to small enzyme activities in mature kernels. Stratificating temperatures and germination inducing precipitations at the same time are inducing pre-harvest sprouting and a high α-amylase activity especially in rye and triticale. It seems as if N-deficiency reduces the possibility of pre-harvest sprouting, on the other hand high N-rates increase the enzymes' activity and promote germination processes in the kernel. Effects of N-fertilization on dormancy are not known.
In the discussion of reasons for an increase of α-amylase activity in sprouted grain caryopses, changes in the relation of the phytohormones gibberellic acid (promoter of enzyme activities) and abscisine acid are mainly presumed.     

Einfluß von Form und Plazierung der N- und P-Düngung auf Wurzelentwicklung, Phosphat-Aufnahme und Wachstum von Sonnenblumen (Helianthus annuus) und Zuckerhirsen (Sorghum bicolor)

Influence of form and placement of N- and P-fertilisation on the root development, the P-uptake, and the growth of sunflower ( Helianthus annum ) and sweet sorghum ( Sorghum bicolor ).
In pot- and rhizotrone-experiments with Sorghum bicolor and Helianthus annuus , a higher P-uptake was achieved by placement of diammonphosphate (DAP) than by either placement of triplesuperphosphate (TSP) or by broadcasting DAP or TSP, respectively. Dual placement of TSP and ammonia increased the P uptake but it was less effective than placement of DAP for sunflowers, but not for sweet sorghum. Placement of nitrogen resulted in a local root accumulation, where ammonia had a greater effect than nitrate for both of the species. Single placement of TSP had no effect on either P uptake or root development.
Thus, the higher P uptake at DAP placement could be attributed to three main factors: the local root accumulation caused by the placement of nitrogen, a specific physiological ammonia-effect, and the lower binding intensity of the phosphate in the DAP-band compared with placed TSP (W erner and S trasser 1993). The improvement in spatial availability caused by the NH₄⁺ -induced root accumulation was of a greater importance for the P-uptake than was the improvement of chemical availability in the DAP-band. The better response of sunflowers in comparison with sweet sorghum was attributed to better acquisition ability in sweet sorghum.     

Einfluß des Lichtangebotes auf das Wachstum und die biologische Stickstoff-Fixierung von Weißklee (Trifolium repens L.)

Influence of light quantity on growth and biological nitrogen fixation of white clover ( Trifolium repens L.)
The influence of photon irradiance (E_p; 100 to 500 μmol m⁻² s⁻¹) and of the photoperiod (16 or 11 h) on growth and nitrogenase activity of nodulated white clover plants was studied in growth chambers at two nitrate levels (1.0 and 7.5 mM NO₃⁻).
Total dry mass production, the root proportion and nitrogenase activity increased with increasing E_p and photoperiod. Nitrogenase activity generally increased proportionally to root mass. Only at low E_p (100 μmol m⁻² s⁻¹) and under a short photoperiod (11 h) was the specific nitrogenase activity per unit root mass reduced. An abrupt change in E_p led to a rapid and parallel change in nitrogenase activity and relative growth rate.
A higher NO₃⁻ concentration in the nutrient solution (7.5 mM) led to a marked decrease in specific nitrogenase activity, but increased growth between 200 and 500 μmol m⁻² s⁻¹ during early development only. At 100 μmol m⁻² s⁻¹, there was no growth response to nitrate, although its effect on nitrogenase activity was more marked than at a higher E_p.
The results show that with changing light quantity, biological nitrogen fixation of white clover adapts to the existing demand for nitrogen and does not limit growth except during early development, even when light supply is low.     

Einfluß des Stickstoffangebotes auf Substanzbildung, Erntegewicht und Qualität der Zuckerrübe unter besonderer Berücksichtigung von Temperatur und Globalstrahlung in Gefäßversuchen

Influence of nitrogen supply on dry matter production, yield and quality of sugar beet with special reference to temperature and irradiance in pot experiments
The influence of nitrogen on yield and quality of sugar beet has been studied in many experiments. In comparison, little is known about the changes in sugar beet metabolism caused by increasing the nitrogen supply. The experiments described in this series of papers deal with the influence of nitrogen supply on mineral metabolism. This first paper describes the influence of nitrogen on dry matter production, yield and quality of beet with special reference to temperature and irradiance. The experiments, conducted in 1988 and 1989 using sand culture in pots, included five nitrogen levels. These treatments were sampled five times during the season and at harvest time. Overall, in 1989 sugar yield (g/pot) was 30 to 50 % greater than in 1988. In 1989 there was only a little more irradiance and duration of sunshine (7 and 11 % respectively) than in 1988, and the larger yield in 1989 was probably caused by a bright period of four weeks in May/June. Where least nitrogen was supplied, deficiency symptoms appeared in early June. When this happened an ammonium-urea solution was added to the leaves: it increased growth, but not enough to equal the white sugar yield of the treatment where the sand was given the same amount of N at the beginning of the season.     

Über den Einfluß von Trockenstreß in unterschiedlichen Entwicklungsphasen auf Wachstum, Blütenabwurf und Ertrag der Sojabohne (Glycine max [L.] Merr.)

The influence of droughtstress during various growth phases on yield parameter and flower drop of the soybean (Glycine max [L.] Merr.) was studied in a pod trial under arid conditions at Alexandria/Egypt. The two cultivars Calland and Williams do not differ in their reaction to droughtstress.
The seed yield was decreased by ca. 18% when two weeks of drought occurred. Droughtstress during the seed filling phase reduced the yield by 25%. This decrease in yield is due to a decrease in pod number and seed number per plant. Flower drop on the main stem is not influenced by droughtstress and there is no relation to the seed yield per plant.     

Einfluß von Hauptbestandsbildner (Lolium multiflorum Lam., Lolium X boucheanum Kunth, Lolium perenne L. und Dactylis glomerata L.), Narbendichte, N-Düngung und Zeit auf Ertrag, Energiedichte, P/E-Quotient und Nitratgehalt

The influence of main species (Lolium multiflorum Lam., Lolium X boucheanum Kunth, Lolium perenne L. and Dactylis glomerata L.), sward density, nitrogen and time on yield, energy content, crudeprotein/energy ratio and nitrate content The aim of this investigation was to determine the influence of different rates of nitrogen fertilizer and of varied sward density on yield and chemical composition of some non-perennial (Lolium multiflorum, Lolium X boucheanum) and some perennial species (Lolium perenne, Dactylis glomerata) in a field experiment. Excepted 600 kg N ha^?l - yr^?1 the non-perennial species produced the highest energy yields. At a fertilization level of 400 kg N ha^?1 yr^?1 had sward density an influence on energy yield of Lolium multiflorum. It appeared that almost the energy content of the Lolium species was higher than in Dactylis glomerata. In most cases there were little differences between the Lolium species. There was a positive correlation between the NFEcontent and the content of water soluble carbohydrates and the energy content which was depressed by applying increasing rates of fertilizer. Generally at the lowest rate of nitrogen used (200 kg N ha^?1 yr^?1) there were positive effects on crude protein/energy ratios. The crude protein/energy ratio was higher of Dactylis glomerata than that of the Lolium species. The nitrate content increased to critical values when applying 400 kg N ha^?1 yr^?1. Dactylis glomerata had the highest and Lolium perenne the lowest nitrate content. At high rate of fertilizer, plots with high sward density sometimes had higher nitrate contents than open swards. The results of the experiment indicate that there are differences in quality even between species with high performance. Regarding the quality of grass swards, future attention should be focused on the main species and on sward density.